In recent years, digital cameras and digital movie cameras have been widely prevalent. Accordingly, it is becoming increasingly popular to store digital photographs and digital movies (hereinafter “photographs” and “movies”) taken by such cameras into a communication device (hereinafter “terminal device”) such as a personal computer (PC), and to view the photographs and the movies. Also, along with the spread of the Internet, the number of terminal devices connected to a network has been increased. As a result, contents (e.g., photographs and movies) stored in a terminal device are exchanged among friends via the network.
Patent Literature 1 discloses a service in which contents including video data and audio data are distributed to clients via a network. In a service as described above, a content provider can distribute contents to multiple clients by accessing a server via operation of his/her own terminal device. Patent Literature 2 discloses a technology for exchanging digital contents between terminal devices, such as mobile terminals, without intervention of a server.